Time flew by, and two hours had passed in the blink of an eye.
As Seimei extracted the Seven-Tails' chakra for the seventeenth time, just as he had predicted, the beast had finally reached its limit.
Likewise, he had also reached his limit.
In the past, the most chakra he ever consumed in a day was around 1.2 million points.
But today, he had used up more than 2 million points.
If that were the only issue, he could have managed.
The real problem was that it wasn't even time for his usual rest period yet.
In other words, he had burned through more chakra in a much shorter amount of time.
How could he not feel exhausted?
Sensing the additional 60,000 chakra points within him, Seimei considered training for another hour. However, after attempting it, he ultimately gave up.
There was no helping it. Right now, even his shadow clones looked completely drained.
Training in this condition wouldn't just be an inefficient use of chakra—it would be a complete waste.
Instead, it made more sense to conserve what he had.
Just as this thought crossed his mind, a wave of drowsiness washed over him, and he let out an uncontrollable yawn.
Covering his mouth, Seimei stopped forcing himself to stay awake.
He picked up the metal sphere containing the sealed Seven-Tails and another nearly empty box that had held fortified ration pills.
Then, gathering his remaining focus, he locked onto the Flying Thunder God mark within the village. In the next instant, he activated the technique and vanished from the island.
When he reappeared, he was back home.
Dismissing the shadow clone that had been left behind to stand guard, Seimei walked into the bathroom, freshened up briefly, and then headed straight for his bedroom.
Without hesitation, he collapsed onto his bed.
The reason he returned to the village to rest was simple: he was completely drained. Once he fell asleep, he would likely lose awareness of any external threats.
Although the training island was remote, he had been using it for a long time. It wasn't impossible that someone might have noticed his routine and set their sights on it.
Even if no outsiders were watching, several high-ranking members of the Uchiha clan knew about the place. The urgent mission he received to support the front lines had been delivered there via messenger hawk.
A secret known to two people is no longer a secret.
So rather than risk it, he preferred to return to the village.
At the very least, Konoha was still safe—for now.
This wasn't cowardice. It was caution.
As the saying goes, "Better safe than sorry." He had worked too hard to reach this point and had no intention of slipping up due to carelessness.
With these thoughts flashing through his mind, Seimei quickly drifted into sleep.
A few breaths later, soft but steady snores filled the room as he entered deep slumber.
The night passed without incident.
---
The Next Morning
As the first rays of sunlight peeked through the gaps in his window, Seimei opened his eyes.
The first thing he noticed was the fine red veins running through them.
That's right—bloodshot eyes.
Clearly, a full night's rest had not restored him to peak condition.
Rubbing his still-aching temples, Seimei turned his gaze toward the metal sphere on his desk, which must have rolled out of his ninja tool pouch at some point.
With a single thought, he extended his mental energy inside.
Inside the sphere, the Seven-Tails had fully recovered, just as he had expected. This realization filled him with mixed emotions.
On one hand, he was pleased. Even after losing two-thirds of its chakra, the Seven-Tails could replenish itself in just a day.
On the other hand, he was troubled. He couldn't fully absorb all of that chakra.
Based on his current condition, Seimei estimated that aside from the 1,016,000 chakra points his own body naturally regenerated each day, he could only digest about 600,000 points from the Seven-Tails.
If he took in more than that, it would interfere with his training the next day, making it counterproductive.
So unless he wanted to waste 400,000 chakra points daily, he needed another solution.
A heavy silence filled the room as Seimei sat cross-legged on his bed, deep in thought.
After a long while, he finally opened his eyes and muttered, "Looks like it's time to put my backup plan into action."
From the moment he decided to extract chakra from the Seven-Tails, he had anticipated the possibility of overflow. So he had already come up with a contingency plan.
The idea was simple: take inspiration from Tsunade's Yin Seal and create a chakra reservoir within his own body to store any excess.
That way, he could release it whenever necessary.
Some might argue that since he already had the Seven-Tails providing him with chakra daily, any excess could just go to waste.
But Seimei didn't see it that way.
He had always been resourceful, and he wasn't about to let all that chakra go to waste.
Besides, 400,000 points per day was no small amount.
If he could store it over time, then once his Sharingan and body evolved further and could handle greater stress, the accumulated chakra would undoubtedly be a major asset.
Additionally, in critical moments, this stored chakra could grant him explosive bursts of power, increasing his combat potential.
Sure, at his current level, he wasn't sure what kind of situation would require an extra 400,000 chakra points.
But it was always better to have it and not need it than to need it and not have it, right?
So he decided to create the chakra reservoir.
As for how to do it, he already had a plan.
Much like the subspace within the metal sphere, he would use "Universal Sealing" to carve out a similar storage space within his own body.
After all, the human body was an excellent chakra conductor.
The network of chakra pathways running through it functioned like a series of high-speed highways, efficiently transporting energy to any part of the body.
By incorporating these pathways into his design, constructing a chakra reservoir wouldn't be difficult.
However, he needed to carefully choose its location.
For maximum absorption efficiency, placing it near his heart would be ideal.
The heart was the "Dead Gate" of the body and a major convergence point for chakra pathways, making it the easiest place to gather energy.
But if he wanted better control over the seal, his forehead would be the best option.
The forehead was the most accessible point for mental energy, making it the optimal location for chakra manipulation.
After careful consideration, Seimei chose the latter.
Not just for ease of control over the Universal Sealing technique, but also because of his Byakugan.
Since merging with him, his Byakugan hadn't shown any clear way to actively evolve. Its growth had only been tied to his increasing mental and physical attributes.
Of course, that was largely because he hadn't dedicated much time to researching it. Otherwise, he would have figured something out by now.
Still, there was no denying that evolving the Byakugan was far more challenging than the Sharingan.
Unlike the Sharingan, which evolved gradually from one tomoe to three, then into the Mangekyō and Eternal Mangekyō, the Byakugan's evolution jumped straight to the Tenseigan—on par with the Rinnegan.
That kind of leap naturally made the process more difficult.
But Seimei was different.
From his status panel, it seemed his Byakugan would follow a step-by-step evolution, much like the Sharingan.
That made things much easier.
His current idea was to create a chakra-rich environment to stimulate its evolution.
It was well known that merging Byakugan could lead to an impure form of the Tenseigan, with chakra volume playing a crucial role.
If he replicated those conditions, would it trigger an evolution?
Seimei didn't know.
But he was willing to find out.
With his mind made up, he wasted no time.
After washing up and having a hearty meal, he left a shadow clone in the village.
Then, he teleported back to the island.